Continuing the meta-auto-behaviour-change effort started here, I’m publishing a few extracts from my PhD thesis as I write it up (mostly from the literature review, and before any rigorous editing) as blog posts over the next few months. The idea of how architecture can be used to influence behaviour was central to this blog when it started, and so it’s pleasing to revisit it, even if makes me realise how little I still know.

“There is no doubt whatever about the influence of architecture and structure upon human character and action. We make our buildings and afterwards they make us. They regulate the course of our lives.”Winston Churchill, addressing the English Architectural Association, 1924

In designing and constructing environments in which people live and work, architects and planners are necessarily involved in influencing human behaviour. While Sommer (1969, p.3) asserted that the architect “in his training and practice, learns to look at buildings without people in them,” it is clear that from, for example, Howard’s Garden Cities of To-morrow (1902), through Le Corbusier’s Ville Contemporaine and La Ville radieuse, to the Smithsons’ ‘Streets in the sky’, there has been a long-standing thread of recognition that the way people live their lives is directly linked to the designed environments in which they live. Whether the explicit intention to influence behaviour drives the design process—architectural determinism (Broady, 1966: see future blog post ‘POSIWID and determinism’)—or whether the behaviour consequences of design decisions are only revealed and considered as part of a post-occupancy evaluation (e.g. Zeisel, 2006) or by social scientists or psychologists studying the impact of a development, there are links between the design of the built environment and our behaviour, both individually and socially.Continue reading →

Professor Neal Kumar Katyal of Georgetown University Law School, best-known for being (successful) lead counsel in the Hamdan v. Rumsfeld case dealing with Guantanamo Bay detainees, has also done some important work on the use of design as a method of law enforcement in both the digital and built environments.

This article, ‘Architecture as Crime Control’, specifically addresses itself to a legal and social policy-maker audience in terms of the areas of focus and the arguments used, but is also very relevant to architects and designers open to being enlightened about the strategic value of their work. Specifically with regard to ‘architectures of control’ and ‘design for behaviour change’, as one might expect, there are many useful examples and a great deal of interesting analysis. In this review, I will try to concentrate on examples and design techniques given in the article, along with some of the thinking behind them – the most useful aspects from the point of view of my own research – rather than attempting to analyse the legal and sociological framework into which all of this fits.

Katyal starts by acknowledging how the “emerging field of cyberlaw, associated most directly with Lawrence Lessig” has brought the idea of ‘code’ constraining behaviour to a level of greater awareness, but suggests that the greater permanence and endurance of architectural changes in the real world – the built environment – may actually give greater potential for behaviour control, as opposed to the “infinitely malleable” architecture of cyberspace:

It is time to reverse-engineer cyberlaw’s insights, and to assess methodically whether changes to the architecture of our streets and buildings can reduce criminal activity.

A theme to which Katyal returns throughout the article is that the policy response to James Wilson and George Kelling’s influential ‘Broken Windows’ – “an architectural problem in crime control” – has largely been a law enforcement one (“prosecution of minor offenses like vandalism in an attempt to deter these ‘gateway crimes'”) instead of actual architectural responses, which, Katyal argues, could have a significant and useful role in this field.

Design principles

Before tackling specific architectural strategies, Katyal discusses the general area of using “design principles” to “influence, in subtle ways, the paths by which we live and think” – a great summary of many of the techniques we’ve considered on this blog over the last couple of years, though not all have been subtle – and gives some good examples:

Fast food restaurants use hard chairs that quickly grow uncomfortable so that customers rapidly turn over

Elevator designers place the numerals and floor indicator lights over people’s heads so that they avoid eye contact and feel less crowded

Supermarkets have narrow aisles so that customers cannot easily talk to each other and must focus on the products instead

(We’ve also seen the opposite effect cited, i.e. using wider aisles to cause customers to spend longer in a particular aisle – clearly, both effects could be employed in different product areas within the same supermarket, to suit whatever strategy the retailer has. There are plenty of other tricks too.)

And, in a footnote, Katyal cites Personal Space by Robert Sommer, which provides:

other examples, such as a café that hired an architect to design a chair that placed “disagreeable pressure on the spine if occupied for over a few minutes” and Conrad Hilton’s decision to move couches out of hotel lobbies to minimise the number of lingering visitors.

(Sommer’s work sounds interesting and relevant, and I look forward to investigating it*)

As Katyal puts it, “with strategies like these, private architects are currently engaging in social control.”

(2) Instill a sense of territoriality so that residents develop proprietary attitudes and outsiders feel deterred from entering a private space;

(3) Build communities and avoid social isolation;

(4) Protect targets of crime.

Before expanding on the practical and legal application of each of these mechanisms, Katyal makes the point that while they can often “work in synergy… natural surveillance is most effective when social isolation is minimized and when design delays the perpetration of crime,” there can be conflicts and any strategy needs to be developed within the context of the community in which it is going to be applied:

Effective design requires input by the community. Without such input, security features are likely to be resented, taken down or evaded (consider the ‘security’ doors propped open on campuses today.

(This issue of ‘resentment’ or even ‘inconvenience’ is, I feel, going to be a significant factor in my own studies of environmentally beneficial behaviour-changing products; we shall see.)

Natural surveillance

The idea of natural surveillance is to create situations where areas are overlooked by neighbours, other residents and so on, with the effect being both a crime deterrent (if the criminal knows he is being watched, or might be watched, he may decide against the crime) and to improve the effectiveness of solving the crime afterwards (someone will have seen what happened). Katyal cites Jane Jacobs‘ argument that diversity of use can be an important way of bringing about natural surveillance – preferably with different activities occurring throughout the day, to ensure that there is always a population there to keep any eye on things. However, short of this kind of deliberate diversity planning, there are specific techniques that can be used on individual buildings and their surroundings to increase natrual surveillance; Katyal suggests the addition of windows facing onto public spaces, ensuring sight lines down corridors and alleyways, positioning windows so that neighbours can watch each other’s houses, bringing parking areas in front of stores rather than out of sight behind them, and making sure hallways and lobbies are clearly visible to passers-by. He gives the example of redesigning the layout of a school’s grounds to increase the opportunity for natural surveillance:

[In the first image] the informal areas are blocked form sight and far from school grounds. Because no central place for congregation exists, students are spread over the grounds, and there is insufficient density for monitoring. The four open entrances and exits facilitate access to the school and escape.
…
[In the second image,] through the designation of formal gathering areas, other places become subtly off-limits to students. Indeed, those who are present in such areas are likely to attract suspicion…. the formal gathering areas are naturally surveilled by building users… [and] are long and thin, running alongside the school windows, and two hedges prevent students from going fuarther away. Moreover, the west entrance, which had the least potential for surveillance, has been closed…

Lighting can also be a major method of increasing natural surveillance:

First, it helps anyone viewing a situation to see it more clearly and thereby deters some crimes by increasing the powers of perception of those watching. Second, it encourages people to be in the area in the first place because the greater visibility creates a sense of security. The more eyes on the street, the more visibility constrains crime.

(Incidentally, Katyal comments – having interviewed an architect – that the use of yellow street lighting “can increase the crime rate by making streets (and individuals on them) look menacing”, hence a tendency for some urban developers to move to white lighting instead.)

Territoriality

Territoriality – also much of the focus of defensible space (which I’ll discuss in a later post) – “both provides an incentive for residents to take care of and monitor an area and subtly deters offenders by warning them that they are about to enter a private space.” Some of Katyal’s examples are wonderfully simple:

“An entrance raised by a few inches” is “a successful symbolic barrier… people are aware of minor graduations of elevation and may refrain from entry if they sense a gradual incline”. (Elevation can also lead to reverence/respect, either directly – e.g. steps leading up to a courthouse – or indirectly, causing a visitor to bow his/her head on approach)

Monuments and markers can also demarcate the transition from public space into private space… A study of burglaries in Salt Lake City… revealed that houses with nameplates had lower rates of intrusion than those without them.

One rather simple way is to place two buildings in an ‘L’ formation with a fence that completes the triangle. Children can play in the open space, and adults can look out of their windows at their children.

Katyal also includes these diagrams from “a group of British architects”:

In the first, a series of buildings lacks a common entrance, and pedestrians cut through the property. The addition of a simple overhead arch, however, creates a sense of private space:

Images originally from Stollard, P. Crime Prevention Through Housing Design and included in Katyal’s article.

Building community

The third main mechanism, building community, is also heavily interlinked with the idea of defensible space. The aim here is to encourage a sense of community, by creating spaces which cause people to interact, or even reducing the number of dwellings in each individual set so that people are more likely to recognise and come to know their neighbours – something many architects have instinctively tried to do anyway over the past 20 years or so, though not always explicitly with crime reduction in mind:

…even the placement of seats and benches can bring people together or divide them, creating what architects call, respectively, sociopetal and sociofugal spaces. Some architects self-consciously create sociofugal spaces by, for example, designing chairs in airports that make it difficult for people to talk to each other.

Practically, ‘building community’ would necessarily appear to be slightly more nebulous than some of the other mechanisms, but even techniques such as encouraging people to spend more time in communal areas such as a laundry (and hence potentially interact more) can be important here.

Strengthening targets

There are a number of simple examples of target hardening or strengthening given:

Placing deadbolts lower on door frames

(presumably to make kicking them open more difficult)

Having doors in vulnerable locations swing outward

Raising fire escapes to put them out of easy reach

Reducing the size of letter-box openings

If a robber can stand on top of a trash bin and reach a second-floor window, the bin should be placed far from the window

Prickly shrubs placed outside of windows can also deter crime

A duct that spews hot air can be placed near a ground-floor window to deter entry

Smells can also be strategically harnessed either to induce people to come outside or keep them away

The FBI building is built on stilts to minimize damage in the event of a bomb detonation at street level

To decrease the likelihood of presidential assassination, a stretch of Pennsylvania Avenue in front of the White House was barricaded and closed to car traffic

Interestingly, Katyal makes the point that where potential crime targets can be strengthened without making it overly obvious that this has been done, the benefits may be greater:

Modern technology permits targets to be hardened in ways that are not obvious to the public. Strong plastics, graffiti-resistant paint, and doors with steel cores are a few examples. These allow architects to disguise their efforts at strengthening targets and thus avoid sending a message that crime is rampant.
…
Some forms of target hardening are suboptimal in that visibility evinces a fear of crime that can cause damage to the fabric of a community and even increase crime rates.

He again later returns to this point:

Subtle architecture that gently reinfoces law-abiding norms and prevents a degree of intrusion is to be preferred to explicit and awkward physical barricades that reflect the feeling that a community is under siege. Cheap wire fences do not express a belief in the power of law or norms; rather, they reflect the opposite. The same can be said for ugly iron bars on windows, which express the terror of crime as powerfully as does any sign or published crime statistic.
…
A whole host of architectural strategies – such as the placement of doors and windows, creation of semipublic congregation spaces, street layout alterations, park redesign, and many more – sidestep creating an architecture dominated by the expression of fear. Indeed, cheap barricades often substitute for these subtler measures. Viewed this way, gated communities are a byproduct of public disregard of architecture, not a sustainable solution to crime.[my emphasis]

(This last point is especially interesting to me – I must admit I am fascinated by the phenomenon of gated communities and what effect they have on their inhabitants as well as on the surrounding area, both in a Ballardian sense (Running Wild, Cocaine Nights, Super-Cannes) and, more prosaically, in terms of what this voluntary separation does to the community outside the gates. See also the quote from architect John Thompson in my forthcoming post reporting what’s happening at the former Brunel Runnymede Campus)

Other aspects

One point to which Katyal repeatedly returns is – a corollary of the above – the concept of architectural solutions as entities which subtly reinforce or embody norms (desirable ones, from the point of view of law enforcement) rather than necessarily enforce them in totality:

Even the best social codes are quite useless if it is impossible to observe whether people comply with them. Architecture, by facilitating interaction and monitoring by members of a community, permits social norms to have greater impact. In this way, the power of architecture to influence social norms can even eclipse that of law, for law faces obvious difficulties when it attempts to regulate social interaction directly.

…

Architecture can prevent crimes even when criminals believe the probability of enforcement is low… one feature of social norms strategies is that they are often self-enforcing.

I think this is a crucial point, and is applicable in other ‘architectures of control’ techniques outside of the built environment and the specific issues of crime. Norms can be extremely powerful influencers of behaviour, and – to take my current research on changing user behaviour to reduce environmental impact – the ability to design a desirable norm into a product or system, without taking away the user’s sense of ownership of, and confidence in, the product, may well turn out to be the crux of the matter.

As (I hope) will be clear, much of Katyal’s analysis seems applicable to other areas of ‘Design for/against X’ where human factors are involved – not just design against crime. So, for example, here Katyal is touching on something close to the concepts of perceived affordances (and disaffordances) in interaction design:

Psychological evidence shows that criminals decode environmental ‘cues’ to assess the likelihood of success of a given criminal act… the design of a meeting table influences who will speak and when, and who is perceived to have a positionof authority. It is therefore no great shock that the eight months of negotiation that preceded the 1969 Paris Peace Talks largely centred on what the physical space of the negotiating table would be. It is said that Machiavelli designed a political meeting chamber with a ceiling that looked asif it were about to collapse, reasoning that it would induce politicians to vote quickly and leave.
…
Winston Churchill… went so far as to claim that the shape of the House [of Commons] was essential to the two-party system and that its small size was critical for ‘free debate':
…
“The party system is much favoured by the oblong form of chamber… the act of crossing the floor is one which requires serious consideration. I am well informed on this matter, for I have accomplished that difficult process, not only once but twice.”

Significant points are also made is about displacement (or “geographic substitution”) of crime: do architectual measures (especially target hardening and obvious surveillance, we might assume) not simply move crime elsewhere? (We’ve discussed this before when looking at blue lighting in public toilets.) Katyal argues that, while some displacement will, of course, occur, this is not always direct substitution. Locally-based criminals may not have knowledge of other areas (i.e. the certainty that these will not be hardened or surveilled targets), or indeed, where crime is opportunistic, the “costs” imposed by travelling elsewhere to commit it are too high. Equally:

Many devices, such as steel-reinforced doors, strong plastics, and the like are not discernible until a criminal has invested some energy and time. These forms of precaution will thus increase expected perpetration cost and deter offenders without risking substantial displacement.

Also, the fact that increased police presence (for example) in a crime ‘hot-spot’ may also lead to crime displacement, is generally not seen as a reason for not increasing that presence: some targets simply are more desirable to protect than others, and where architectural measures allow police to concentrate elsewhere, this may even be an advantage.

More specific examples

Aside from the analysis, there are a great many architectures of control and persuasion examples dotted throughout Katyal’s article, and while they are somewhat disparate in how I present them here, they are all worth noting from my point of view, and I hope interesting. Apart from those I’ve already quoted above, some of the other notable examples and observations are:

…the feeling of being crowded correlates with aggression. Architects can alleviate the sensation of crowding by adding windows that allow for natural light, by using rectangular rooms (which are perceived to be larger than square ones), and by employing light-colored paints. When people perceive more space, they tend to become less hostile.

While the results should not be overemphasized, psychologists have found results showing that various colors affect behavior and emotions. The most consistent such finding is that red induces a higher level of arousal than do cool colors like green and blue. Another study indicated that people walked faster down a hallway painted red or orange than down one painted in cooler colors. After experimenting with hundreds of shade, Professor Schauss identified a certain shade of pink, Baker-Miller, as the most successful color to mediate aggression… prisoners in Baker-Miller pink cells were found to be les abusive than those in magnolia-colored cells.

For some existing housing projects, the government could pass regulations requiring retrofitting to prevent crime. Small private or semiprivate lawns near entrances can encourage feelings of territoriality; strong lighting can enhnace visibility; staining and glazing can increase contrast; and buildings refaced with a diversity of pleasing finishes can reflect individuality and territoriality. Large open spaces can be subdivided to encourage natural surveillance.

Edward I enacted the Statute of Winchester, a code designed to prevent the concealment of robbers… [which included a] provision [which] directly regulated environmental design to reduce crime… highways had to be enlarged and bushes had to be cleared for 200 feet on either side of the highway.

…certain buildings [being strategically placed in an area] such as churches, may reduce the crime rate because they create feelings of guilt or shame in potential perpetrators and because the absence of crime against such structures furthers visible social order.

Crimes that directly interfere with natural surveillance should… be singled out for special penalties. Destroying the lighting around a building is one obvious example. Another would be attempts by criminals to bring smoke-belching trucks onto a street before robbing an establishment.

Summary

Ultimately, Katyal’s aim seems to be to encourage policy-makers to see architectural measures as a potentially important aspect of crime reduction, given sensible analysis of each situation, and he suggests the use of Crime Impact Statements – possibly as a requirement for all new development – in a similar vein to Environmental Impact Statements, and leading to similar increases in awareness among architects and developers. Building codes and zoning policies could also be directed towards crime reduction through architectural strategies. Insurance companies, by understanding what measures ‘work’ and which don’t, could use premiums to favour, promote and educate property owners, similarly to the way that widespread adoption of better design for fire protection and prevention was significantly driven by insurance companies.

In this sense, a public (i.e. governmental) commitment to use of architectural strategies in this way would make the process much more transparent than individual private developers adopting ad hoc measures, and, with sensible analysis of each case, could assist local law enforcement and engage communities in reinforcing ‘desirable’ norms and ‘designing away’ some aspects of their problems – though Katyal makes it very clear that architecture alone cannot do this [my emphasis]:

None of this should be mistaken for architectural determinism or its derivative belief that good buildings alone will end crime. These hopes of ‘salvation by bricks’ are illusory. But our rejection of this extreme should not lead us to the opposite extreme view, which holds that physical settings are irrelevant to human beliefs and action. Architecture influences behavior; it does not determine it.

*Katyal also later cites Sommer’s Social Design for the example of airports that “prevent crime by replacing bathroom entrance doors with right-angle entrances that permit the warning sounds of crime to travel more freely and that reduce the sense of isolation”. I’d always assumed that (as with the toilet facilities in many motorway services here in the UK), this was to reduce the number of surfaces that a toilet user would have to touch – a similar strategy to having the entrance doors to public toilet areas pushable/elbowable/nudgable by users leaving the area, rather than forcing recently-washed hands to come into contact with a pull-handle which may not be especially clean. See also Sara Cantor’s thoughts on encouraging handwashing.

Simply, the concept is a chair which progressively collapses as the user’s home energy use becomes excessive, and restores itself when corrective action is taken (such as turning devices off):

Chairs are designed to support a person’s weight: this is taken for granted, but what if that feature were taken away from the user until they have done their bit? This is a way of forcefully highlighting the issue, so they cannot ignore it any more.

The idea is for a range of products with similar ideas – one of Ben’s lecturers, Christian McLening, also mentioned to me the idea of a light cord that retracts gradually the more energy is used, and a bookshelf that similarly tilts gradually. The light cord sounds intriguing, but by making the cord more difficult to reach (to turn it off), it perhaps signifies the opposite of what’s intended. Along the lines of what Crosbie Fitch suggested here, lights which gradually dimmed as the house’s energy consumption increased might be an interesting alternative. But Ben’s aim was very much to play with the ‘punishment’ aspect:

Design and Punishment was, to begin with, a look at designing a product that could make saving energy in the home easier through better awareness. The products force the user to cut down on their energy consumption. Instead of trying to make energy saving easier, the range of products forces the user to save [energy] or suffer a punishment.

Again, the line between forcing the user (physically) to behave in a certain way, and persuading him or her to change behaviour, is not a distinct one; as Toby commented here, both are methods of control, and both are powerful, but in cases such as this where the user would have to choose to purchase the chair voluntarily (Ben’s chair is only a concept product, but the principle stands), the persuasion/coercion would be two/three-pronged: inspiring the purchase in the first place/motivating the user to use it where more convenient alternatives are available, and the actual forcing aspect when the user’s behaviour is changed, rather than the product being abandoned in frustration/annoyance.

Thousands of people live and work here without making a single decision about right and wrong. The moral order is engineered into their lives along with the speed limits and the security systems.

Re-reading Ballard’s excellent Super-Cannes, since the way the winter afternoon sunlight suddenly caught a building a few days ago made me think sharply, momentarily, of the vast technology parks of Sophia-Antipolis. The above quote describes, essentially, architecture of control in a structural, sub-surface, context: in the sense of Robert Moses‘ low bridges, perhaps. Not just artefacts with politics, but entire environments and systems with agendas.

(This is the first Friday quote for a long time. In fact there’s only been one previously; I’ll try to make it a regular feature of the blog. They won’t always be about architectures of control, but I’ll endeavour to make sure they’re always interesting.)

First, an apology for anyone who’s had problems with the RSS/Atom feeds over the last month or so. I think they’re fixed now (certainly Bloglines has started picking them up again) but please let me know if you don’t read this. Oops, that won’t work… anyway:

‘Gadgets as Tyrants’ by Xeni Jardin, looks at digital architectures of control in the context of the 2007 Consumer Electronics Show in Las Vegas :

Many of the tens of thousands of products displayed last week on the Vegas expo floor, as attractive and innovative as they are, are designed to restrict our use… Even children are bothered by the increasing restrictions. One electronics show attendee told me his 12-year-old recently asked him, “Why do I have to buy my favorite game five times?” Because the company that made the game wants to profit from each device the user plays it on: Wii, Xbox, PlayStation, Game Boy or phone.

At this year’s show, the president of the Consumer Electronics Association, Gary Shapiro, spoke up for “digital freedom,” arguing that tech companies shouldn’t need Hollywood’s permission when they design a new product.

David Rickerson equally kindly sends me details of a modern Panopticon prison recently built in Colorado – quite impressive in a way:

…Architects hit a snag when they realized too much visibility could create problems.

“We’ve got lots of windows looking in, but the drawback is that inmates can look from one unit to another through the windows at the central core area of the ward,” Gulliksen says. “That’s a big deal. You don’t want inmates to see other inmates across the hall with gang affiliations and things like that.”

To minimize unwanted visibility, the design team applied a reflective film to all the windows facing the wards. Deputies can see out, but inmates cannot see in. Much like the 18th-century Panopticon, the El Paso County jail design keeps inmates from seeing who is watching them.

“Yes, but it isn’t really $5,000,” you say. It is if you are Cingular, and you handle a few billion messages like this each quarter.

… [I] assumed that I would be able to install iChat myself. Or better still Adium, which supports AIM, MSN, ICQ, and Jabber. But I will not be able to do that because … it will not be possible to install applications on the iPhone without the approval of Cingular and Apple… But as a consumer, I have a choice. And for now the ability to install any application that I want leaves phones powered by Windows Mobile, Symbian, Linux, RIM, and Palm OS with some major advantages over the iPhone.

Aside from the price discrimination (and business model) issue (see also Control & Networks), one thing that strikes me about a phone with a flat touch screen is simply how much less haptic feedback the user gets.

I know people who can text competently without looking at the screen, or indeed the phone at all. They rely on the feel of the buttons, the pattern of raised and lowered areas and the sensation as the button is pressed, to know whether or not the character has actually been entered, and which character it was (based on how many times the button is pressed). I would imagine they would be rather slow with the iPhone.

A couple of years ago, after seeing a programme by Jon Ronson, I was reading about the First Earth Battalion and came across a link to an apparently real document, Nonlethal Weapons: Terms and References, edited by Robert J Bunker of the Institute for National Security Studies at the USAF Academy, Colorado. It’s available on the Memory Hole, here.

Amid the various physical, physiological and psychological techniques described (some of which I’ll be looking at in later posts, as they’re pertinent to architectures of control), one section especially stood out – from page 15 of the document:

Now, these are interesting techniques. I don’t know if ‘hologram’ is being used in the right way here, since these sound like simple projections, e.g. onto clouds (or maybe, in the case of the ‘ghost’ appearing next to the drug lord’s bedside, some kind of volumetric display). And whether such projections would really work in terms of scaring or misleading the enemy – who knows?

Have they ever actually been used? Dummy tanks are a well-known way of deceiving an enemy, but would people be taken in by a “projection of the image of an ancient god”? How would they know that what they were seeing was the “ancient god”? If the image used were such a common representation that it was instantly recognisable, wouldn’t it seem obviously fake? Or would any giant figure looming over a city scare people sufficiently, whether or not they realised what it was supposed to represent? (It’s been suggested that the Angels of Mons, if they existed, may have been “images of angels that the Germans had projected onto the clouds at the outbreak of the battle in order to try and scare the troops on the opposite side…But apparently this idea had backfired, in that the troops had seen these images and believed them to be St George, Joan of Arc, actually leading them against the Germans.”)

The projection of “soldier-force images” has more credibility. Odd atmospheric effects seem to be the explanation behind the various reflected “cities in the sky” that have occasionally been seen: taking this further, it is surely possible to create a mirage-like effect of a massed army to intimidate an enemy.

So, outside of the military context, is there potential for this kind of false image to be used to manipulate and control the public? Not obviously, perhaps, but as the police in many countries become increasingly militarised in outlook (particularly in “security” situations), would the tactic of projecting images of massed officers (maybe with riot shields covering their faces, to make extensive detail less necessary) be considered? Cardboard cutout police cars are occasionally used to scare motorists, as are fake speed cameras (often placed by members of the public) and, of course, fake CCTV cameras.

“While projection on to a building is not illegal as such, you will be asked to move on by the police because laser projection is viewed as a distraction to drivers and hence a hazard,” says Dominic Bean, formerly head of marketing and business Development at NESCOT. He used projections to promote North East Surrey College of Technology and found that the response from the authorities was far from harsh. “Policemen on Epsom Downs (ten miles away from the projection site) spotted our projection on to Tolworth Towers – near the A3 in Surrey,” says Bean. “It took them nearly 50 minutes to drive over and ask for the image to be removed. They were amazed to see it, and saw the ‘fun’ side.

Guerrilla ‘photon bombing’ or ‘projection bombing’ clearly has a lot of potential for allowing members of the public, activists and counterculture groups to promote their messages, but so far doesn’t appear to have been used for truly subversive ends on a large scale. There is some very clever work going on in this field, such as Troika’s SMS Guerilla Projector, but imagine a politician’s press conference where giant images of his opponent or opposing slogans are projected behind him, or a televised sports event where logos of the sponsor’s rivals are projected (by someone in the crowd) onto the faces of players being shown in close-up. It may have already happened; if not, it won’t be long before it does.